Fossil Fuels
• How it Works
• Advantages / Disadvantages
• Is it Renewable?
How it Works
• Coal is crushed to a fine dust and burnt.
• Oil and gas can be burnt directly.
Coal
Crude
Oil
Natural Gas
Advantages
• Very large amounts of electricity can be
generated in one place using coal, fairly
cheaply.
• Transporting oil and gas to the power
stations is easy.
• Gas-fired power stations are very
efficient.
• A fossil-fuelled power station can be
built almost anywhere, so long as you can
get large quantities of fuel to it.
Disadvantages
• Basically, the main drawback of fossil fuels is
pollution.
• Burning any fossil fuel produces carbon dioxide,
which contributes to the "greenhouse effect",
warming the Earth., and sulphur dioxide, a gas that
contributes to acid rain.
• Strip mining destroys large areas of the landscape.
• Coal-fired power stations need huge amounts of
fuel, which means train-loads of coal almost
constantly.
• This means covering a large area of countryside
next to the power station with piles of coal.
Is it renewable?
• Fossil fuels are not a renewable
energy resource.
• Once we've burned them all, there isn't
any more, and our consumption of fossil
fuels has nearly doubled every 20 years
since 1900.
• This is a particular problem for oil,
because we also use it to make plastics
and many other products.
• How it Works
• Advantages / Disadvantages
• Renewable?
Nuclear Power
How it Works
• The reactor uses Uranium rods as fuel, and
the heat is generated by nuclear fission:
neutrons smash into the nucleus of the
uranium atoms, which split roughly in half and
release energy in the form of heat.
• Carbon dioxide gas or water is pumped
through the reactor to take the heat away,
this then heats water to make steam.
• The steam driven turbines stores electrical
energy in the generators.
Advantages
• Nuclear power costs about the same as
coal, so it's not expensive to make.
• Does not produce smoke or carbon
dioxide, so it does not contribute to the
greenhouse effect.
• Produces huge amounts of energy from
small amounts of fuel.
• Produces small amounts of waste.
• Nuclear power is reliable.
Disadvantages
• Although not much waste is produced, it is very,
very dangerous. It must be sealed up and buried
for many thousands of years to allow the
radioactivity to die away.
• For all that time it must be kept safe from
earthquakes, flooding, terrorists and everything
else. This is difficult.
• Nuclear power is reliable, but a lot of money has
to be spent on safety - if it does go wrong, a
nuclear accident can be a major disaster.
• People are increasingly concerned about this - in
the 1990's nuclear power was the fastestgrowing source of power in much of the world. In
2005 it was the second slowest-growing.
Is it renewable?
• Nuclear energy from Uranium is not
renewable.
• Once we've dug up all the Earth's
uranium and used it, there isn't any
more.
Solar Power
• How it Works
• Advantages / Disadvantages
• Renewable?
How it Works
• Solar Cells
(really called "photovoltaic", "PV" or
"photoelectric" cells) that convert light
directly into electricity.
Solar Cell Panels
Advantages
• Solar energy is free - it needs no fuel
and produces no waste or pollution.
• In sunny countries, solar power can be
used where there is no easy way to get
electricity to a remote place.
• Handy for low-power uses such as solar
powered garden lights and battery
chargers, or for helping your home
energy bills.
Disadvantages
• Doesn't work at night.
• Very expensive to build solar power
stations, although the cost is coming
down as technology improves.
• Can be unreliable unless you're in a very
sunny climate.
Is it renewable?
• Solar power is renewable. The Sun will
keep on shining anyway, so it makes
sense to use it.
Would hydroelectric power work
here in Delaware? Why or why
not? Explain your answers.
• Very expensive for little energy.
• No large fast moving rivers in DE.
• No suitable place to put the dam.
• Destroy wildlife and ecosystems!
Wind Power
• How it Works
• Advantages / Disadvantages
• Renewable?
Early
Windmills
• The Babylonians
and Chinese were
using wind power
to pump water
for irrigating
crops 4,000
years ago, and
sailing boats were
around long
before that.
How it Works
• The Sun heats our atmosphere unevenly, so
some patches become warmer than others.
• These warm patches of air rise (Convection
currents), other air blows in to replace them and we feel a wind blowing.
• We can use the energy in the wind by building
a tall tower, with a large propeller on the top.
• The wind blows the propeller round, which
turns a generator to produce electricity.
Advantages
• Wind is free, wind farms need no fuel.
• Produces no waste or greenhouse gases.
• The land beneath can usually still be
used for farming.
• Wind farms can be tourist attractions.
• A good method of supplying energy to
remote areas.
Disadvantages
• The wind is not always predictable - some days
have no wind.
• Suitable areas for wind farms are often near the
coast, where land is expensive.
• Some people feel that covering the landscape
with these towers is unsightly.
• Can kill birds - migrating flocks tend to like
strong winds. However, this is rare, and we tend
not to build wind farms on migratory routes
anyway.
• Can affect television reception if you live nearby.
• Can be noisy.
Is it renewable?
• Wind power is renewable. Winds will
keep on blowing, it makes sense to use
them.
Tidal Power
• How it Works
• Advantages / Disadvantages
• Renewable?
How it Works
• A huge dam (called a "barrage") is built across
a river estuary. When the tide goes in and
out, the water flows through tunnels in the
dam.
• The ebb and flow of the tides can be used to
turn a turbine, or it can be used to push air
through a pipe, which then turns a turbine.
Large lock gates, like the ones used on canals,
allow ships to pass.
Underwater
Turbines
•
•
•
•
•
•
•
Advantages
Once you've built it, tidal power is free.
It produces no greenhouse gases or other waste.
It needs no fuel.
It produces electricity reliably.
Not expensive to maintain.
Tides are totally predictable.
Offshore turbines and vertical-axis turbines are
not expensive to build and do not have a large
environmental impact.
Disadvantages
• A barrage across an estuary is very expensive to
build, and affects a very wide area - the
environment is changed for many miles upstream
and downstream.
• Many birds rely on the tide uncovering the mud
flats so that they can feed. Fish can't migrate,
unless "fish ladders" are installed.
• Only provides power for around 10 hours each
day, when the tide is actually moving in or out.
• There are few suitable sites for tidal barrages
Fish Ladders
Is it renewable?
• Tidal energy is renewable. The tides
will continue to ebb and flow, and the
energy is there for the taking.
Hydroelectric Power
• How it Works
• Advantages and
Disadvantages
• Renewable?
How it Works
• A dam is built to trap water, usually in a
valley where there is an existing lake.
• Water is allowed to flow through
tunnels in the dam, to turn turbines and
thus drive generators.
Hoover Dam
Advantages
• Once the dam is built, the energy is virtually
free.
• No waste or pollution produced.
• Much more reliable than wind, solar or wave
power.
• Water can be stored above the dam ready to
cope with peaks in demand.
• Hydro-electric power stations can increase to
full power very quickly, unlike other power
stations.
• Electricity can be generated constantly.
Disadvantages
• The dams are very expensive to build.
However, many dams are also used for flood
control or irrigation, so building costs can be
shared.
• Building a large dam will flood a very large area
upstream, causing problems for animals that used
to live there.
• Finding a suitable site can be difficult - the
impact on residents and the environment may be
unacceptable.
• Water quality and quantity downstream can be
affected, which can have an impact on plant life.
Is it renewable?
• Hydro-electric power is renewable.
The Sun provides the water by
evaporation from the sea, and will keep
on doing so.
Pumped Storage
Reservoir
• How it Works
• Advantages / Disadvantages
• Renewable?
How it Works
• Water is pumped up to the top reservoir at
night, when demand for power across the
country is low.
• When there's a sudden demand for power,
the "headgates" (huge taps) are opened, and
water rushes down the tunnels to drive the
turbines, which drive the powerful
generators.
• The water then collects in the bottom
reservoir, ready to be pumped back up later.
Advantages
• Without some means of storing energy
for quick release, we'd be in trouble.
• Little effect on the landscape.
• No pollution or waste.
Disadvantages
• Expensive to build.
• Once it's used, you can't use it again
until you've pumped the water back up.
Is it renewable?
• It's not really a power station, but a
means of storing energy from other
power stations.
So the question doesn't apply.
Wave Power
• How it Works
• Advantages / Disadvantages
• Renewable?
How it Works
• At a wave power station, the waves
arriving cause the water in the chamber
to rise and fall, which means that air is
forced in and out of the hole in the top
of the chamber.
• We place a turbine in this hole, which is
turned by the air rushing in and out.
• The turbine turns a generator.
Wave Power Station
Advantages
• The energy is free - no fuel needed, no
waste produced.
• Not expensive to operate and maintain.
• Can produce a great deal of energy.
Disadvantages
• Depends on the waves - sometimes you'll
get loads of energy, sometimes almost
nothing.
• Needs a suitable site, where waves are
consistently strong.
• Some designs are noisy. But then again, so
are waves, so any noise is unlikely to be a
problem.
• Must be able to withstand very rough
weather.
Is it renewable?
• Wave power is renewable.
Geothermal Power
• How it Works
• Advantages / Disadvantages
• Renewable?
How it Works
• Hot rocks underground heat water to
produce steam.
• We drill holes down to the hot region,
steam comes up, is purified and used to
drive turbines, which drive electric
generators.
Advantages
• Geothermal energy does not produce any
pollution, and does not contribute to the
greenhouse effect.
• The power stations do not take up much room, so
there is not much impact on the environment.
• No fuel is needed.
• Once you've built a geothermal power station,
the energy is almost free. It may need a little
energy to run a pump, but this can be taken from
the energy being generated.
Disadvantages
• The big problem is that there are not
many places where you can build a
geothermal power station.
• Sometimes a geothermal site may "run
out of steam", perhaps for decades.
• Hazardous gases and minerals may come
up from underground, and can be
difficult to safely dispose of.
Is it renewable?
• Geothermal energy is renewable.
The energy keeps on coming, as long as
we don't pump too much cold water
down and cool the rocks too much.
Biomass
• How it Works
• Advantages / Disadvantages
• Renewable?
How it Works
Advantages
• It makes sense to use waste materials
where we can.
• The fuel tends to be cheap.
• Less demand on the fossil fuels.
Disadvantages
• Collecting or growing the fuel in
sufficient quantities can be difficult.
• We burn the biofuel, so it makes
greenhouse gases just like fossil fuels
do.
• Some waste materials are not available
all year round.
Is it renewable?
• Biomass is renewable, as we're going to
carry on making waste products anyway.
We can always plant & grow more sugar
cane and more trees, so those are
renewable too.
4. So after doing your
research, what is the main
reason why we need to find
Alternative fuels?
We are running out of fossil
fuels at an alarming rate,
worldwide.
5. What are the disadvantages
and advantages of having a
Hydroelectric Dam on the Red
Clay Creek here in Delaware?
Advantages Disadvantages
•
•
•
•
Virtually free energy
No waste or pollution
Constant energy
Reliable energy source
•
•
•
•
•
•
Expensive
Environmental impact
Large area flooded
Little energy produced
Affect water quality
Not a suitable site to build
6.Which type of alternative
energy would be more the
most efficient (best) to use
here in Delaware?
Explain your answer.
(Biomass, Hydroelectric, Nuclear, Solar, Wind, Hydrogen Fuel, Geothermal)
Scantron Sheets
• Name
• Mr. Madigan
• DTHS
• Earth
Science
• Date 6-8-12
• Leave class
blank!
• Period?
• Student ID #